1. Field of the Invention
Methods and apparatuses consistent with the present invention relate to a multiband Orthogonal Frequency Division Multiplexing (OFDM) receiver, and more particularly, to effectively compensating for a frequency offset of a received signal in a multiband OFDM scheme.
2. Description of Related Art
A multiband OFDM scheme generally indicates a method of transmitting a signal while hopping in a plurality of frequency bands per OFDM symbol unit, and particularly, indicates a modulation technology which is used for a particular wireless communication system such as an Ultra Wideband (UWB) system. In this instance, the multiband OFDM system may transmit and receive a large number of data per time unit by transmitting data using a plurality of frequency bands with a regular frequency band.
In most wireless communication systems, a frequency offset occurs when a frequency of an oscillator of a transmitting end does not precisely match a frequency of an oscillator of a receiving end. Specifically, when the frequency offset exists, the receiving end may not detect a signal precisely and thus, a multiband OFDM receiver which precisely detects a received signal is required.
As an example, a multiband OFDM receiver according to a related art estimates a frequency offset in a frequency domain using a pilot symbol, and compensates for the estimated frequency offset. Also, the multiband OFDM receiver estimates a remaining frequency offset and then compensates for the estimated remaining frequency offset in the frequency domain with a decision-directed method using a modulated pilot symbol. Also, the multiband OFDM receiver according to the related art estimates a frequency offset using a pilot symbol in a frequency band and then compensates for the estimated frequency offset in a time domain. Also, the multiband OFDM receiver estimates a remaining frequency offset and compensates for the estimated remaining frequency error in the frequency domain.
However, the multiband OFDM receiver according to the related art may not track a quick phase change which is caused by a large frequency offset. Therefore, as a frequency offset increases, a performance of the multiband OFDM receiver significantly deteriorates. To overcome the above-described disadvantages, a multiband OFDM receiver which can effectively compensate for a frequency offset of a received signal in a multiband OFDM receiver is required.